Maps

A map is:

(map key value ... )

To access maps there are the following forms:

Return the value associated with key in map:
```
(map-get map key)
```
Set keys in map to values:
```
(map-set map key val ... )
```
Update keys in map to values. Note that this form requires all the keys to exist:
```
(map-update map key val ... )
```

NOTE: This syntax for processing maps has stablized, but may change in the future!

There is also an alternate short form map functions:

These are based on the MACLISP array reference forms. They take the same arguments as their longer alternatives.